Stadia may not have had a perfect launch due to its early communication issues with the community among other things, but for the most part it's a service that works pretty well in many cases. And most users seem to be happy with it.
Now they'll have even more reasons to be happy, as it looks like Destiny 2: The Collection will stay free for Stadia Pro members. For now at least. A report from 9To5Google yesterday notes an announcement from Google on the Stadia subreddit.
In the announcement, Google says that Destiny 2: The Collection will remain available for Pro members for the "foreseeable future."
Google doesn't give an exact time frame
As mentioned, the game will remain free for now for any Stadia Pro members. This is great for anyone that may end up getting a Premiere Bundle around Christmas time. As they would likely not get their codes to activate Stadia until January.
Some suspected that Destiny 2: The Collection would disappear from the Pro free games lineup after December, so this is a nice reaffirmation that it's sticking around.
Keeping that in mind, Google does say for the forseeable future. And that means the game will eventually leave the Pro lineup for anyone that hasn't already claimed it. When is what it really comes down to.
The good news is that Google says it will "do its best to communicate ahead of time" when or if that time comes. If you're waiting on Stadia until after the first of the year, you should still be able to claim Destiny 2: The Collection.
It would be wise not to wait too long on it though if you do happen to want it. As you won't lose it once it's claimed, so long as you still sub to Pro.
Will it ever come to Stadia Base?
Saying anything other than who knows would be speculation. Because at this point in time Google hasn't said much about whether or not Destiny 2 would be an exclusive title for Pro members.
Users in the official Stadia subreddit believe that because Destiny 2 is now a free-to-play game on PC and consoles, save for the Shadowkeep expansion and season passes, that Stadia Base will get the same treatment.
This is a logical belief, because it makes sense. The fact of the matter is Google hasn't confirmed whether or not Base users would have access for free like on other platforms. So it's entirely possible that it might not happen.
Another thing to consider is that Every game that is offered at a deal for Pro members, including the other three free games, can be purchased at a listed price. Destiny 2: The Collection can't. So that may suggest that Google has no intention of making it available for free to Base members.